Function mark_cursor_pds_created 

pub async fn mark_cursor_pds_created(
    pool: &SqlitePool,
    did: &str,
    feed_url: &str,
) -> Result<()>

Mark a cursor’s PDS readState record as CREATED after the flush that first created it, so subsequent flushes emit an update instead of another create. Idempotent; a no-op if the row is gone.